Methods and system of automating track circuit calibration

ABSTRACT

A method for calibrating a track circuit is provided. The track circuit includes a transmit processing unit, a receive processing unit, and a plurality of rails coupled in series to form a track section having a first end and a second end. The transmit processing unit is coupled to the track section adjacent the first end. The receive processing unit is coupled to the track section adjacent the second end. The method includes operating the transmit processing unit so that a first voltage is applied to the track section, operating the receive processing unit to detect a first current signal, and if a parameter of the first current signal is not within a predetermined acceptable range, then communicating with the transmit processing unit so that the transmit processing unit applies a second voltage to the track section, the second voltage having a different magnitude than the first voltage.

BACKGROUND OF THE INVENTION

This invention relates generally to railroad systems, and morespecifically, to methods and system of automatically calibrating trackcircuits.

A rail track circuit typically is used to detect whether a train ispresent on a track section. Such circuit also can be used to detectbroken rails within the track section and/or can be used to transmitsignal aspect information through the rails. A typical track circuitincludes rails in electrical series with a signal transmitter and asignal receiver. The signal transmitter applies a voltage, sometimesreferred to as a transmit voltage, to the rails. As a result, a currentsignal, sometimes referred to as a receive current, is transmittedthrough the rails. The receive current is detected by the receiver.

When a train composed of one or multiple railcars is located on thetrack section of the track circuit, the wheels of the railcars act as ashunt between the rails and form a shunt path. The shunt path creates anelectrical short between the rails at the location of the train, andsuch short path effectively prevents the receive current from beingreceived/detected by the signal receiver.

Over time, environmental conditions and rail conditions can change.These changing conditions impact ballast resistance of the trackcircuit. Generally, leakage paths occur through the ballast, and theleakage resistance of such paths varies due to the changing conditions.The varying leakage resistance impacts the receive current. The trackcircuit therefore is configured, or calibrated, to operate over a rangeof ballast resistance.

Due to the changing conditions, over time, the track circuit may requirere-calibration. Known calibration techniques involve positioning human“maintainers” with two-way radios at the transmitter and receiver. Themaintainer at the transmitter communicates data related to the appliedvoltage to the maintainer at the receiver. The receiver maintainer theninforms the transmitter maintainer of the current signal received at thereceiver. Adjustments are made to both the transmitter and receiver sothat the track circuit operates as desired over the ballast resistancerange. Another known calibration technique is for a single humanmaintainer to perform track circuit calibration by traveling betweentransmitter and receiver sites (i.e., locations) to make eachadjustment. As such, the process of manually calibrating the trackcircuit settings may be costly, inefficient and/or time-consuming.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, a method for calibrating a track circuit is provided. Thetrack circuit includes a transmit processing unit, a receive processingunit, and a plurality of rails coupled in series to form a track sectionhaving a first end and a second end. The transmit processing unit iscoupled to the track section adjacent the first end. The receiveprocessing unit is coupled to the track section adjacent the second end.The method includes operating the transmit processing unit so that afirst voltage is applied to the track section, operating the receiveprocessing unit to detect a first current signal, and if a parameter ofthe first current signal is not within a predetermined acceptable range,then communicating with the transmit processing unit so that thetransmit processing unit applies a second voltage to the track section,the second voltage having a different magnitude than the first voltage.

In a further aspect, a track circuit is provided. The track circuitincludes a remote system, a transmit processing unit, and a receiveprocessing unit. The remote system is configured to electronicallycouple to at least one of the transmit processing unit and the receiveprocessing unit. The track circuit further includes a plurality of railscoupled in series to form a track section having a first end and asecond end. The transmit processing unit coupled to the track sectionadjacent the first end. The receive processing unit coupled to the tracksection adjacent the second end. The transmit processing unit isconfigured to apply a first voltage to the track section duringoperation. The receive processing unit is configured to detect a firstcurrent signal during operation. If a parameter of the first currentsignal is not within a predetermined acceptable range, then the receiveprocessing unit is configured to communicate with the transmitprocessing unit such that the transmit processing unit applies a secondvoltage to the track section. The second voltage has a differentmagnitude than the first voltage.

In another aspect, a track circuit is provided. The track circuitincludes a transmit processing unit, a receive processing unit, and aplurality of rails coupled in series to form a track section having afirst end and a second end. The transmit processing unit is coupled tothe track section adjacent the first end. The receive processing unitcoupled to the track section adjacent the second end. The transmitprocessing unit is configured to apply a first voltage to the tracksection during operation, and the receive processing unit is configuredto detect a first current signal during operation. If a parameter of thefirst current signal is not within a predetermined acceptable range,then the receive processing unit is configured to communicate with thetransmit processing unit such that the transmit processing unit appliesa second voltage to the track section. The second voltage has adifferent magnitude than the first voltage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a track circuit.

FIG. 2 is a flowchart depicting a method of calibrating the trackcircuit shown in FIG. 1.

FIG. 3 is a flowchart depicting a method of calibrating the trackcircuit 100 shown in FIG. 1 from a remote location.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic illustration of at least one track circuit 100 inaccordance with an exemplary embodiment of the present invention. Trackcircuit 100 enables automatic evaluation and calibration of a section ofthe railroad track. Track circuit 100 includes a plurality of rails 12and 14 coupled in series to form a track section 101 having a first end16 and a second end 18. Track section 101 may include a plurality ofties (not shown) coupling rails 12 and 14 together. The ties are laid inthe ground and substantially covered with ballast (i.e., small stones)to hold the ties in place. Over time, environmental conditions and railconditions can change. The changing conditions impact ballast resistanceof track circuit 100. Generally, leakage paths occur through theballast, and the leakage resistance impacts the current levels. Trackcircuit 100 therefore is configured, or calibrated, to operate over arange of ballast resistance, as will be discussed in more detail below.

Track circuit 100 further includes a transmit processing unit 103 and areceive processing unit 105. In the exemplary embodiment, adjustmentsare made to both units 103 and 105 so that track circuit 100 operates asdesired over a given ballast resistance range. In the exemplaryembodiment, transmit processing unit 103 is coupled to adjacent tracksection first end 16, and receive processing unit 105 is coupled toadjacent track section second end 18. Transmit processing unit 103 isconfigured to apply a first voltage across track section 101 duringoperation. For example, transmit processing unit 103 may be configuredto apply a voltage across track section 101 at end 16, therebygenerating a current in a direction shown in FIG. 1. Receive processingunit 105 is configured detect a first current through, for example,track section 101 at end 18. In an alternative embodiment, unit 103 hassimilar components and similar functionality to unit 105, and unit 105has similar components and similar functionality to unit 103.

In the exemplary embodiment, transmit processing unit 103 includes atleast one energy source 110 and at least one receiver 116, and receiveprocessing unit 105 includes at least one energy source 112 and at leastone receiver 114. Moreover, in the exemplary embodiment, each unit 103and unit 105 includes at least one program including at least onearithmetic logic unit. In an alternative embodiment, each unit 103 andunit 105 does not include at least one arithmetic logic unit. Generally,each unit 103 and 105 of a coded track circuit includes arithmetic logicunits, and each unit 103 and 105 of a non-coded track circuit does notinclude arithmetic logic units. For example, non-coded track circuitunits have only an on or off current detection. With an on or offcurrent detections, the on or off transmit voltage needs to be highenough to allow current detection.

In the exemplary embodiment, computer programs, or software, are storedin memory device 206 within unit 103 and/or unit 105. A suitable memorydevice 206 in the preferred embodiment is an electrically erasableprogrammable read only member (hereinafter “EEPROM”). Moreover, it isunderstood that other types of memory could be utilized, such as simpleread only memory (ROM), or programmable read only member (PROM), or, ifthe ability to reprogram the ROM is desirable, erasable programmableread only memory (EPROM), which are conventionally erased by exposure toultraviolet light or FLASH memory.

Track circuit 100 may be calibrated, operated, and monitored from aremote location. For example, in one embodiment, transmit and receiveprocessing units 103 and 105 are configured to communicate with a remotesystem (not shown) via a wireless network. In the exemplary embodiment,communication between the remote system and units 103 and 105 is basedon a client-server relationship using established protocols such as, butnot limited to, Internet Protocol (IP). In an alternative embodiment,communication between the remote system and units 103 and 105 mayinclude any suitable means that enables track circuit 100 to function asdescribed herein.

FIG. 2 is a flowchart 198 depicting a method of calibrating at least aportion of track circuit 100. In the exemplary embodiment, each unit 103and 105 is selectively operable between a calibration mode and anoperational mode. In the exemplary embodiment, a railroad operator(i.e., a human “maintainer”) selects local calibration mode 199 to begin201 calibration of track section 101.

In the exemplary embodiment, unit 103 is configured to apply 202 avoltage 203 across track section 101, and unit 105 is configured todetect 205 a current 204 flowing through track section 101. In analternative embodiment, the track section 101 is calibrated in asubstantially similar matter to the method described herein; however,unit 105 is configured to apply 202 voltage 203 across track section101, and unit 103 is configured to detect current 204 flowing throughtrack section 101.

Moreover, in the exemplary embodiment, at least one unit 103 and/or unit105 includes memory device 206 for at least temporarily storing variousvoltage and current parameters and a predetermined current thresholdrange. For example, the transmit voltage may be approximately 2 voltswhile the receive current parameter may be approximately 1.5 amps andthe threshold range may be set at approximately 0.5 amps. Thepredetermined current threshold range 223 may be input as a suggestedthreshold by the maintainer. In the exemplary embodiment, thepredetermined current threshold range 223 is approximately 0.5-6.0 amps.In an alternative embodiment, the predetermined current threshold range223 is pre-programmed within unit 105.

In the exemplary embodiment, unit 105 is configured to adjust 208 therange 223 based upon the changing ballast condition. For example, if thetrack circuit is set up by the maintainer when the ballast leakage islow (i.e., good conduction down the rail), then the transmit voltage maybe set to approximately 1 volt and the receive current may beapproximately 2 amps. For example, if a train is detected in the trackcircuit, the train shorts the rails in the track circuit causing a smallamount of current to be received at unit 105 (i.e. receiver). As such,the threshold could be set to approximately 0.6 amps such that if thereceive current is below 0.6 amps, the track circuit will declare that atrain is on the track circuit. However, if the ballast leakage increases(i.e. low conduction down the rail exists), then the receive currentwill be less due to the ballast leakage. Therefore, if the receivecurrent drops below 0.6 amps at unit 105 (i.e. receiver), a train is“detected” on the track circuit due to the ballast conditions eventhough no train actually occupies the track. As such, range 223 isadjusted based upon the changing ballast conditions.

Once current threshold range 223 has been adjusted based upon theballast conditions, unit 105 is configured to apply 212 the magnitude ofrange 223 and the parameters of signal 204 across track section 101, andunit 103 is configured to detect 214 the magnitude of range 223 andsignal 204 flowing through track section 101.

In the exemplary embodiment, at least one of unit 103 and/or unit 105also includes a logic module 220 including a function block 222.Function block 222 within unit 103 is configured to compare 216 at leastone parameter of a detected current signal to the current thresholdrange 223.

After comparison of a parameter of current signal 204 to currentthreshold range 223, if a parameter of current signal 204 is not withinthe range, then unit 103 is configured to automatically adjust 225voltage 203 and unit 103 is configured to apply a second voltage acrosstrack section 101. In the exemplary embodiment, the second voltage has adifferent magnitude than the first voltage 203, and the method,described herein, repeats until a predetermined parameter of currentsignal 204 is within the range 223.

On the other hand, after comparison of a parameter of current signal 204to current threshold range 223, if current signal 204 is within therange 223, then unit 105 is configured to communicate with unit 103 suchthat unit 103 maintains the magnitude of first voltage signal 203.Moreover, in the exemplary embodiment, if current signal 204 is withinrange 223, then unit 105 is configured to communicate with unit 103 suchthat unit 103 records first voltage signal 203 parameters, first currentsignal 204 parameters, and current threshold range 223 parameters.

In the exemplary embodiment, a timing mechanism (not shown) is coupledto each unit 103 and 105. The timing mechanism is configured to switcheach respective unit 103 and 105 to the operational mode after apredetermined time to prevent units 103 and 105 from remaining incalibration mode 199. For example, unit 103 and/or 105 would switch fromcalibration mode 199 to the operational mode after approximately 1minute of inactivity in calibration mode 199. The default for switchingout of calibration mode 199 may be to a safe default value or to thepre-determined values. In an alternative embodiment, once track section101 has been calibrated, then the maintainer may return each unit 103and/or 105 to the operational mode. Moreover, at least one unit 103and/or 105 may be coupled to an output display (not shown) such thatvarious stored parameters may be output to the display.

During operation, in the exemplary embodiment, the maintainer setstransmit processing unit 103 to local calibration mode 199 to begin 201automatic calibration of track section 101. In calibration mode 199,unit 103 applies 202 a first voltage signal 203 (i.e., test pulses)across track section 101. In an alternative embodiment, signal 203 istransmitted from unit 103 as a predefined pulse pattern, a message,and/or any other communication media that enables track circuit 100 tofunction as described herein.

In the exemplary embodiment, unit 105 detects 205 first current signal204. In the exemplary embodiment, unit 105 at least temporarily storesthe parameters of signal 203 and range 223 in memory device 206. In theexemplary embodiment, unit 105 may adjust 208 the range 223 based uponchanging ballast conditions.

In the exemplary embodiment, unit 105 adjusts 208 the range 223 basedupon the changing ballast condition. For example, if the track circuitis set up by the maintainer when the ballast leakage is low (i.e., goodconduction down the rail), then the transmit voltage may be set toapproximately 1 volt and the receive current may be approximately 2amps. For example, if a train is detected in the track circuit, thetrain shorts the rails in the track circuit causing a small amount ofcurrent to be received at unit 105 (i.e. receiver). As such, thethreshold could be set to approximately 0.6 amps such that if thereceive current is below 0.6 amps, the track circuit will declare that atrain is on the track circuit. However, if the ballast leakage increases(i.e. low conduction down the rail exists), then the receive currentwill be less due to the ballast leakage. Therefore, if the receivecurrent drops below 0.6 amps at unit 105 (i.e. receiver), a train is“detected” on the track circuit due to the ballast conditions eventhough no train actually occupies the track. As such, range 223 isadjusted based upon the changing ballast conditions.

Once current threshold range 223 has been adjusted based upon theballast conditions, unit 105 applies 212 the magnitude of range 223 andthe parameters of signal 204 across track section 101, and unit 103detects 214 the magnitude of range 223 and signal 204 flowing throughtrack section 101.

Function block 222 within unit 103 then compares 216 at least oneparameter of signal 204 to the current threshold range 223. In theexemplary embodiment, after comparison of a parameter of current signal204 to current threshold range 223, if a parameter of first currentsignal 204 is not within the current threshold range 223, then unit 103automatically adjusts 225 first voltage 203 to a second voltage.Specifically, in the exemplary embodiment, second voltage has adifferent magnitude than first voltage signal 203. Unit 103 then applies202 the second voltage across track section 101. As such, unit 105detects a second current, and the method repeats until a predeterminedparameter of the current signal is within the range.

On the other hand, if after comparison of a parameter of current signal204 to current threshold range 223, the parameter current signal 204 iswithin the range, then unit 103 maintains the magnitude of first voltagesignal 203. Moreover, in the exemplary embodiment, if current signal 204is within range 223, then unit 103 records 218 first voltage signal 203parameters, first current signal 204 parameters, and current thresholdrange 223 parameters. Calibration of track section 101 is complete 219when the various parameters have been recorded by unit 103.

In the exemplary embodiment, when calibration of track section 101 iscomplete, the timing mechanism (not shown) switches each respective unit103 and 105 to the operational mode after a predetermined time toprevent units 103 and 105 from remaining in calibration mode 199. Forexample, unit 103 and/or 105 would switch from calibration mode 199 tothe operational mode after approximately 1 minute of inactivity incalibration mode 199. The default for switching out of calibration mode199 may be to a safe default value or to the pre-determined values. Inan alternative embodiment, once track section 101 has been calibrated,then the maintainer may return each unit 103 and/or 105 to theoperational mode. Moreover, at least one unit 103 and/or 105 may becoupled to an output display (not shown) such that various storedparameters may be output to the display.

FIG. 3 is a flowchart 300 depicting a method of calibrating at least aportion of track circuit 100 from a remote location. In the exemplaryembodiment, each unit 103 and 105 is selectively operable between acalibration mode 301 and an operational mode. In the exemplaryembodiment, track circuit 100 may be calibrated, operated, and monitoredfrom a remote location using a remote system configured to apply asignal to at least one of unit 103 and/or unit 105. For example,transmit and receive processing units 103 and 105 are configured tocommunicate with the remote system (not shown) via a wireless network(not shown). In an alternative embodiment, a railroad operator (i.e., ahuman “maintainer”) selects remote calibration mode 301 to begincalibration of track section 101.

In the exemplary embodiment, the remote system is configured to apply299 a signal to unit 103 instructing unit 103 to operate in calibrationmode 301, and unit 103 is configured to detect 302 the signal from theremove system. In the exemplary embodiment, unit 103 is configured toapply 307 a start-up signal 304 across track section 101. Unit 105 isconfigured to detect signal 304 and is configured to begin 309 automaticcalibration of track section 101. As such, unit 105 is configured toapply 313 a voltage signal 305 across track section 101, and unit 103 isconfigured to detect 312 a current signal 306 flowing through tracksection 101. In an alternative embodiment, the remote system isconfigured to apply a signal to track section 101 instructing unit 105to operate in calibration mode 301. As such, the track section 101 iscalibrated in a substantially similar matter to the method describedherein.

In the exemplary embodiment, at least one of unit 103 and/or unit 105includes a memory device 206 for at least temporarily storing variousparameters and a current threshold range. The current threshold range303 may be input into unit 103 as a suggested threshold by themaintainer. In an alternative embodiment, the current threshold range303 is pre-programmed within unit 103. In the exemplary embodiment, unit103 is configured to adjust the range 303 based upon changing ballastconditions. For example, if the track circuit is set up by themaintainer when the ballast leakage is low (i.e., good conduction downthe rail), then the transmit voltage may be set to approximately 1 voltand the receive current may be approximately 2 amps. For example, if atrain is detected in the track circuit, the train shorts the rails inthe track circuit causing a small amount of current to be received atthe receiver unit. As such, the threshold could be set to approximately0.6 amps such that if the receive current is below 0.6 amps, the trackcircuit will declare that a train is on the track circuit. However, ifthe ballast leakage increases (i.e. low conduction down the railexists), then the receive current will be less due to the ballastleakage. Therefore, if the receive current drops below 0.6 amps at thereceiver unit, a train is “detected” on the track circuit due to theballast conditions even though no train actually occupies the track. Assuch, range 303 is adjusted based upon the changing ballast conditions.

Once current threshold range 303 has been adjusted based upon theballast conditions, unit 105 is configured to apply 316 the magnitude ofrange 303 and the parameters of signal 305 across track section 101, andunit 103 is configured to detect 318 the magnitude of range 303 andsignal 305 flowing through track section 101.

In the exemplary embodiment, at least one of unit 103 and/or unit 105also includes a logic module 220 including a function block 222.Function block 222 within unit 105 is configured to compare at least oneparameter of a detected signal to a threshold range. After comparison ofa parameter of current signal 306 to current threshold range 303, if aparameter of current signal 306 is not within the range, then unit 105is configured to apply a second voltage across track section 101. In theexemplary embodiment, the second voltage has a different magnitude thanthe first voltage 305, and the method, described herein, repeats until apredetermined parameter of current signal 306 is within the range 303.

On the other hand, after comparison of a parameter of current signal 306to predetermined current threshold range 303, if a parameter of currentsignal 306 is within the range, then unit 105 maintains the magnitude offirst voltage signal 305. Moreover, in the exemplary embodiment, ifcurrent signal 306 is within range 303, then unit 105 communicates withunit 103 such that unit 103 records first voltage signal 305 parameters,first current signal 306 parameters, and current threshold range 303parameters.

In the exemplary embodiment, a timing mechanism (not shown) is coupledto at least one unit 103 and/or 105. Once unit 103 records first voltagesignal 305 parameters, first current signal 306 parameters, and currentthreshold range 303 parameters, calibration is substantially complete,and the remote system is configured to apply a signal to the timingmechanism. The signal is configured to switch the timing mechanism fromcalibration mode 301 to the operational mode to prevent units 103 and105 from remaining in calibration mode 301. In an alternativeembodiment, each timing mechanism is configured to switch fromcalibration mode 301 to the operational mode after a predetermined timeto prevent units 103 and 105 from remaining in calibration mode 301. Ina further alternative embodiment, once track section 101 has beencalibrated, then the maintainer may return each unit 103 and/or 105 tothe operational mode. Moreover, at least one unit 103 and/or 105 may becoupled to an output display (not shown) such that various storedparameters may be output to the display.

During operation, in the exemplary embodiment, the remote system applies299 a signal to unit 103 instructing unit 103 to operate in calibrationmode 301, and unit 103 detects 302 the signal. In the exemplaryembodiment, unit 103 communicates with unit 105 such that unit 105applies 307 a start-up signal across track section 101 to begincalibration of track section 101. In the exemplary embodiment, incalibration mode 301, unit 103 applies 307 a start-up signal 304 to unit105. Start-up signal 304 instructs unit 105 to begin calibration orre-calibration of track section 101, and unit 105 begins 309 calibrationor re-calibration. In the exemplary embodiment, unit 105 applies 313first voltage signal 305 across track section 101. In an alternativeembodiment, signal 305 is applied across track section 101 as apredefined pulse pattern, a message, and/or any other communicationmedia that enables track circuit 100 to function as described herein.

In the exemplary embodiment, unit 103 detects 312 a first current signal306. In the exemplary embodiment, unit 103 at least temporarily storesthe parameters of current signal 306 in memory device 206. In theexemplary embodiment, unit 103 adjusts 314 the range 303 based upon thechanges in the condition of the ballast described herein above. When atrain enters a track circuit, the received current drops suddenly andis, therefore, distinguishable from ballast deterioration which causesthe receive current to drop much more slowly.

For example, if the track circuit is set up by the maintainer when theballast leakage is low (i.e., good conduction down the rail), then thetransmit voltage may be set to approximately 1 volt and the receivecurrent may be approximately 2 amps. For example, if a train is detectedin the track circuit, the train shorts the rails in the track circuitcausing a small amount of current to be received at the receiver unit.As such, the threshold could be set to approximately 0.6 amps such thatif the receive current is below 0.6 amps, the track circuit will declarethat a train is on the track circuit. However, if the ballast leakageincreases (i.e. low conduction down the rail exists), then the receivecurrent will be less due to the ballast leakage. Therefore, if thereceive current drops below 0.6 amps at the receiver unit, a train is“detected” on the track circuit due to the ballast conditions eventhough no train actually occupies the track. As such, range 303 isadjusted based upon the changing ballast conditions.

Once range 303 has been adjusted, unit 105 applies 316 the magnitude ofthe parameters signal 305 across track section 101 such that unit 103detects 318 the magnitude of the parameters of signal 305.

Function block 222 within unit 105 compares 320 at least one parameterof current signal 306 to the current threshold range 303. In theexemplary embodiment, after comparison of a parameter of current signal306 to predetermined current threshold range 303, if a parameter ofcurrent signal 306 is not within the predetermined current thresholdrange 303, then unit 105 automatically adjusts 321 voltage 305 andapplies 313 a second voltage across track section 101. Specifically, inthe exemplary embodiment, second voltage has a different magnitude thanfirst voltage 305. As such, unit 103 detects a second current, and themethod repeats until a predetermined parameter of current signal 306 iswithin the range 303.

On the other hand, if after comparison of a parameter of first currentsignal 306 is within the predetermined current threshold range 303, theparameter current signal 306 is within the range, then unit 105maintains the magnitude of first voltage signal 305. Moreover, in theexemplary embodiment, if current signal 306 is within range 303, thenunit 105 communicates with unit 103 such that unit 103 records 322 firstvoltage signal 305 parameters, first current signal 306 parameters, andcurrent threshold range 303 parameters within memory device 206.

Calibration of track section 101 is complete 324 when the variousparameters have been recorded by unit 103. In the exemplary embodiment,once track section 101 is complete, the remote system communicates withat least one of the timing mechanisms (not shown) coupled to unit 103and/or unit 105 such that the remote system instructs the timingmechanism to switch each respective unit 103 and/or 105 to theoperational mode from calibration mode 301 to prevent units 103 and/or105 from remaining in calibration mode 301. In an alternativeembodiment, each timing mechanism switches from calibration mode 301 tothe operational mode after a predetermined time to prevent units 103 and105 from remaining in calibration mode 301. In a further alternativeembodiment, once track section 101 has been calibrated, then themaintainer may return each unit 103 and/or 105 to the operational mode.Moreover, at least one unit 103 and/or 105 is coupled to an outputdisplay (not shown) such that various stored parameters are output tothe display.

The above-described methods and systems enable automatic calibration ofthe transmitting voltage and the receiving current thresholds for atrack circuit of a railroad. Track circuit calibration may be requiredwhen the environment changes and/or when the railroad conditions change.Accordingly, the need for manual setup and calibration is eliminated,thereby facilitating a reduction in the chance for error, in costsand/or time associated with maintenance of the railroad. Moreover, theabove-described methods and system increase the safety of the railroad.

At least one unit 103 and/or 105 may include, but is not limited toincluding, a microprocessor, microcontroller, a microcomputer, aprogrammable logic controller, an application specific integratedcircuit, or any other programmable circuit. Therefore, the termprocessor, as used herein, is not limited to just those integratedcircuits referred to in the art as computers, but broadly refers tomicroprocessors, microcontrollers, microcomputers, programmable logiccontrollers, application specific integrated circuits, and otherprogrammable circuits, and these terms are used interchangeably herein.

As will be appreciated by one skilled in the art and based on theforegoing specification, the above-described embodiments of theinvention may be implemented using computer programming or engineeringtechniques including computer software, firmware, hardware or anycombination or subset thereof, wherein the technical effect is tocalibrate a track circuit. Any such resulting program, havingcomputer-readable code means, may be embodied or provided within one ormore computer-readable media, thereby making a computer program product,i.e., an article of manufacture, according to the discussed embodimentsof the invention. The computer readable media may be, for example, butis not limited to, a fixed (hard) drive, diskette, optical disk,magnetic tape, semiconductor memory such as read-only memory (ROM),and/or any transmitting/receiving medium such as the Internet or othercommunication network or link. The article of manufacture containing thecomputer code may be made and/or used by executing the code directlyfrom one medium, by copying the code from one medium to another medium,or by transmitting the code over a network.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralsaid elements or steps, unless such exclusion is explicitly recited.Furthermore, references to “one embodiment” of the present invention arenot intended to be interpreted as excluding the existence of additionalembodiments that also incorporate the recited features.

Exemplary embodiments of system and method for automatic calibrating arailroad track circuit are described above in detail. The system andmethod illustrated are not limited to the specific embodiments describedherein, but rather, components of the system may be utilizedindependently and separately from other components described herein.Further, steps described in the method may be utilized independently andseparately from other steps described herein.

While the invention has been described in terms of various specificembodiments, those skilled in the art will recognize that the inventioncan be practiced with modification within the spirit and scope of theclaims.

1. A method for calibrating a track circuit, the track circuit includinga transmit processing unit, a receive processing unit, and a pluralityof rails coupled in series to form a track section having a first endand a second end, the transmit processing unit coupled to the tracksection adjacent the first end, the receive processing unit coupled tothe track section adjacent the second end, said method comprising:operating the transmit processing unit so that a first voltage isapplied to the track section; and operating the receive processing unitto detect a first current, and if a parameter of the first current isnot within a predetermined range, then communicating with the transmitprocessing unit so that the transmit processing unit applies a secondvoltage to the track section, the second voltage having a differentmagnitude than the first voltage.
 2. A method in accordance with claim 1further comprising operating the receive processing unit to detect asecond current.
 3. A method in accordance with claim 2 furthercomprising operating the receive processing unit to detect the firstcurrent, and if the parameter of the first current is within thepredetermined range, then communicating with the transmit processingunit so that the transmit processing unit records at least one of amagnitude of the first voltage, a magnitude of the first current, and amagnitude of the second current.
 4. A method in accordance with claim 3further comprising operating at least one of the transmit processingunit and the receive processing unit such that when at least one of themagnitude of the first voltage, the magnitude of the first current, andthe magnitude of the second current is recorded, the track circuitcalibration is complete.
 5. A method in accordance with claim 1 whereinthe track circuit is coupled in electronic data communication to aremote system, said method further comprising operating the remotesystem such that a signal is applied to the transmit processing unitinstructing the transmit processing unit to apply a start-up signal tothe track section.
 6. A method in accordance with claim 1 wherein thetrack circuit is coupled in electronic data communication to a remotesystem, said method further comprising operating the remote system suchthat a signal is applied to the receive processing unit instructing thereceive processing unit to apply a start-up signal to the track section.7. A method in accordance with claim 6 further comprising operating thetransmit processing unit to detect the start-up signal so that thetransmit processing unit applies the first voltage to the track section.8. A track circuit comprising: a remote system; a transmit processingunit and a receive processing unit, said remote system configured forcommunication with at least one of said transmit processing unit andsaid receive processing unit; and a plurality of rails coupled in seriesto form a track section having a first end and a second end, saidtransmit processing unit coupled to said track section adjacent saidfirst end, said receive processing unit coupled to said track sectionadjacent said second end; said transmit processing unit configured toapply a first voltage to said track section during operation for trackcircuit calibration, said receive processing unit configured to detect afirst current during operation, if a parameter of said first current isnot within a predetermined range, then said receive processing unit isconfigured to communicate with said transmit processing unit such thatsaid transmit processing unit applies a second voltage to said tracksection wherein said second voltage has a different magnitude than saidfirst voltage.
 9. A track circuit in accordance with claim 8 whereinsaid receive processing unit is configured to detect a second current.10. A track circuit in accordance with claim 9 wherein said receiveprocessing unit is configured to detect said first current, and if saidparameter of said first current is within said predetermined range, thencommunicating with said transmit processing unit so that said transmitprocessing unit records at least one of a magnitude of said firstvoltage, a magnitude of said first current, and a magnitude of saidsecond current.
 11. A track circuit in accordance with claim 10 whereinsaid track circuit calibration is complete when at least one of saidtransmit processing unit and said receive processing unit record atleast one of the magnitude of said first voltage, the magnitude of saidfirst current, and the magnitude of said second current.
 12. A trackcircuit in accordance with claim 10 wherein said track circuit remotesystem is configured to apply a signal to said transmit processing unitinstructing said transmit processing unit to apply a start-up signal tosaid track section.
 13. A track circuit in accordance with claim 10wherein remote system is configured to apply a signal to said receiveprocessing unit instructing said receive processing unit to apply astart-up signal to said track section.
 14. A track circuit in accordancewith claim 13 wherein said transmit processing unit is configured todetect said start-up signal and to apply said first voltage to saidtrack section in response to detecting the start-up signal.
 15. A trackcircuit comprising: a transmit processing unit; a receive processingunit; and a plurality of rails coupled in series to form a track sectionhaving a first end and a second end, said transmit processing unitcoupled to said track section adjacent said first end, said receiveprocessing unit coupled to said track section adjacent said second end;said transmit processing unit configured to apply a first voltage tosaid track section during operation, said receive processing unitconfigured to detect a first current during operation, if a parameter ofsaid first current is not within a predetermined range, then saidreceive processing unit is configured to communicate with said transmitprocessing unit such that said transmit processing unit applies a secondvoltage to said track section wherein said second voltage has adifferent magnitude than said first voltage.
 16. A track circuit inaccordance with claim 15 wherein said receive processing unit isconfigured to detect a second current.
 17. A track circuit in accordancewith claim 16 wherein said receive processing unit is configured todetect said first current, and if said parameter of said first currentis within said predetermined range, then communicating with saidtransmit processing unit so that said transmit processing unit recordsat least one of a magnitude of said first voltage, a magnitude of saidfirst current, and a magnitude of said second current.
 18. A trackcircuit in accordance with claim 17 wherein said track circuitcalibration is complete when at least one of said transmit processingunit and said receive processing unit record at least one of themagnitude of said first voltage, the magnitude of said first current,and the magnitude of said second current.